Willson Contreras has hamstring strain

The first step is for Contreras to be pain free, which will likely take about two weeks. The Cubs will then step up his rehab process, and the team will have a better idea of the timeline then.

The loss of Contreras creates a huge hole in the Cubs lineup. Since the All-Star break, he has led the team, batting .311 with 10 home runs and 29 RBIs. Contreras has been such a key piece that manager Joe Maddon inserted him in left field last Saturday and at first base on Wednesday to keep his bat in the lineup.

Contreras ranked fourth in the National League among clean-up batters with a .305 average. In 31 games there, he had 13 home runs and 35 RBIs.

Alex Avila, 30, acquired from the Tigers at the Trade Deadline, will handle most of the catching duties while Contreras is sidelined.

This is Caratini’s second stint with the Cubs. In 11 games from June 28-Aug. 1, he was 5-for-26 (.192), including a home run on July 30.

Carrie Muskat has covered the Cubs since 1987, and for MLB.com since 2001. She writes a blog, Muskat Ramblings. You can follow her on Twitter @CarrieMuskat and listen to her podcast. This story was not subject to the approval of Major League Baseball or its clubs.